Science terms starting with K

74 terms

K Smoke- Smoke in various concentrations can cause significant problems for people with respiratory ailments.
K AMS Cold Air Mass
K Corona In solar-terrestrial terms, of the white-light corona (that is, the corona seen by the eye at a total solar eclipse), that portion which is caused by…
K-capture The capture by an atom's nucleus of an orbital electron from the first K-shell surrounding the nucleus.
K-Index A measure of the thunderstorm potential based on vertical temperature lapse rate, moisture content of the lower atmosphere, and the vertical extent of the…
Kanamycin An antibiotic of the aminoglycoside family that poisons translation by binding to the ribosomes.
kanr Kanamycin resistance gene. (See Selectable marker.)
Kaplan Turbine A type of turbine that has two blades whose pitch is adjustable. The turbine may have gates to control the angle of the fluid flow into the blades.
kappa chain One of two classes of antibody light chains. The other is a lambda chain.
karyogamy The fusion of nuclei or nuclear material that occurs at fertilization during sexual reproduction.
karyogram A diagrammatic representation of the full chromosome set of a species, highlighting characteristic physical features of individual chromosomes.
karyokinesis The division of a cell nucleus. See: meiosis; mitosis.
Karyotype All of the chromosomes in a cell or an individual organism, visible through a microsope during cell division.
Katabatic Wind A wind that is created by air flowing downhill.
Katafront A front where the warm air descends the frontal surface (except in the low layers of the atmosphere).
KB Abbreviation for kilobase (of single-stranded nucleic acid).
kbp Abbreviation for kilobase pairs (of double-stranded DNA ).
kcat The catalytic rate constant that characterizes an enzyme-catalysed reaction. The larger the kcat value, the faster the conversion of substrate into…
kcat/Km The catalytic efficiency of an enzyme-catalysed reaction. The greater the value of kcat/Km, the more rapidly and efficiently the substrate is converted…
Kd Abbreviation for dissociation constant. Describes the strength of binding (or affinity) between molecules and their ligands . See: avidity.
kDa Abbreviation for kiloDalton. A unit of molecular mass equal to 1000 Dalton.
Keetch-Byrum Drought Index An index used to gage the severity of drought in deep duff and organic soils.
Kelvin One Kelvin degree is equivalent to one Celsius degree. The difference between the two temperature scales: All motion within an atom ceases at zero Kelvin…
Kelvin Temperature Scale An absolute temperature scale in which a change of 1 Kelvin equals a change of 1 degree Celsius; 0°K is the lowest temperature on the Kelvin scale.
Kelvin Waves Fluctuations in wind speed at the ocean surface at the Equator result in eastward propagating waves, known as Kelvin Waves.
Kelvin-Helmholtz Waves Vertical waves in the air associated with wind shear across statically-stable regions.
Kelvin-Helmoltz waves Vertical waves in the air associated with wind shear across statically stable regions.
Keratin An extremely tough protein substance found in hair, nails, skin, and cornea.
Keratinocytes Cells that synthesize keratin and are found in the skin, hair, and nails. A fibrous protein is produced by keratinocytes and may be hard or soft.
Kerogen Solid, waxy mixture of rock is heated to high temperatures, the kerogen is vaporized.
Kerosene A type of heating fuel derived by refining crude oil that has a boiling range at atmospheric pressure from 400 degrees to 550 degrees F.
KEV One thousand electron volts.
Key observation point(s) (KOP) One or a series of points on a travel route or at a use area or a potential use area, where the view of a management activity would be most revealing.
killer T cell T cells that kill cells displaying recognized antigens.
Kilo A prefix meaning "thousand".
kilobase (Abbreviation: kb). A length of single-stranded nucleic acid composed of 1000 bases.
Kilobase (kb) Unit of length for DNA fragments equal to 1000 nucleotides.
kilobase pairs (Abbreviation: kbp). A length of double-stranded DNA composed of 1000 base pairs.
Kilopascal The internationally recognized unit used by the Atmospheric Environment Service for measuring atmospheric pressure. Abbreviated kPa.
Kilovolt (kV) One thousand volts.
Kilovolt-Ampere (kVa) A unit of apparent power, equal to 1,000 volt-amperes; the mathematical product of the volts and amperes in an electrical circuit.
Kilowatt A unit of electrical power equal to 1,000 watts (W).
Kilowatt (kW) A standard unit of electrical power equal to one thousand watts, or to the energy consumption at a rate of 1000 Joules per second.
Kilowatt hour (kWh) A measure of energy equivalent to the expenditure of one kilowatt for one hour. For example, 1 kWh will light a 100-watt light bulb for 10 hours.
Kilowatt Hours A measurement for electricity use.
Kilowatt-hour A unit or measure of electricity supply or consumption of 1,000 Watts over the period of one hour; equivalent to 3,412 Btu.
Kilowatthour (kWh) A measure of electricity defined as a unit of work or energy, measured as 1 kilowatt (1,000 watts) of power expended for 1 hour.
kinase An enzyme that catalyses the transfer of a phosphate group from a high energy state (as in ATP) to another molecule.
Kinetic Energy Energy available as a result of motion that varies directly in proportion to an object's mass and the square of its velocity.
kinetics Dynamic processes involving motion. Often used as a suffix to indicate studies involving movement or rates of reactions.
kinetin A cytokinin.
kinetochore Structure at the centromere of eukaryotic chromosomes. The kinetochore consists of inner and outer electron dense plates and a central zone containing…
kinetosome Granular cytoplasmic structure which forms the base of a cilium or flagellum. Synonym: basal body.
kinin A substance promoting cell division. In plant systems, the prefix cyto- has been added (cytokinin ) to distinguish it from kinin in animal systems.
Kiva An underground (or partially underground) ceremonial room or chamber used in ancient and modern Pueblo villages.
Klason lignin Lignin obtained from wood after the non-lignin components of the wood have been removed with a prescribed sulfuric acid treatment.
Klenow fragment A truncated form of DNA polymerase I from E. coli, used extensively for the production of synthetic DNA molecules as it retains polymerase and…
Klystron An electron tube used as a low-power oscillator or a high-power amplifier at ultrahigh frequencies.
Km A dissociation constant that characterizes the binding of an enzyme to a substrate.
Kneewall A wall usually about 3 to 4 feet high located that is placed in the attic of a home, anchored with plates between the attic floor joists and the roof…
Knob A small hilltop that is round in shape.
Knock In Replacement of a gene by a mutant version of the same gene using homologous recombination.
Knock Out Inactivation of a gene by homologous recombination following transfection with a suitable DNA construct.
Knock-out mouse A mouse that has had one or both copies of a specific gene deleted or inactivated.
knockout A mutant individual, in which a single functional gene has been replaced by a non-functional form of the gene.
Knot (abbrev. Kt) Unit of speed used in navigation, equal to 1 nautical mile (the length of 1 minute latitude) per hour or about 1.
Known Geothermal Area (KGA) A region identified by the U.S. Geological Survey as containing geothermal resources.
Knuckles Slang for lumpy protrusions on the edges, and sometimes the underside, of a thunderstorm anvil.
Knutson-Vandenberg Act (KV) Federal law that allows the U.S. Forest Service to collect money from a timber sale for resource enhancement, protection, and improvement work in the…
Kp Index A 3-hourly planetary geomagnetic index of activity generated in Gottingen, Germany, based on the K Index from 12 or 13 stations distributed around the…
kraft process Chemical pulping process in which lignin is dissolved by a solution of sodium hydroxide and sodium sulfide.
KT (Knot)- Unit of speed used in navigation, equal to 1 nautical mile (the length of 1 minute latitude) per hour or about 1.15 statue miles per hour, or 0.
KTS Knots
Kyoto Protocol This is an international agreement struck by 159 nations attending the Third Conference of Parties (COP) to the United Nations Framework Convention on…